Although uveitis sometimes occurs in association with Behcet's disease, sarcoidosis, Harada's disease, etc., its pathogenesis is obscure in 50 to 70% of the patients. There are a number of findings on uveitis which can be classified into, for example, iridocyclitis (anterior uveitis), retinochoroiditis (posterior uveitis), panuveitis, intermediary uveitis, etc. depending on the inflammation site. To treat uveitis, steroids are commonly used, however, steroids produce undesirable side effects. Therefore, it has been urgently required to develop drugs efficacious against uveitis.
On the other hand, methotrexate (MTX), which is a folic acid metabolism antagonist, has been employed as a carcinostatic agent in treating acute leukemia, malignant lymphoma, etc. Also, MTX is known as an immunosuppressive agent and used mainly for preventing acute graft-versus-host reactions in bone marrow transplantation. Moreover, it is known that administration of MTX in a small dose is efficacious in treating rheumatoid arthritis.